本部分ISO 21069规定了一种滚筒制动试验，用于确定ISO 1176中定义的最大授权总质量（代码ISO-MO8）超过3.5 t，属于UNECE R.E.3中定义的M2、M3、N2、N3、O3和O4类且配备全功率空气（气动）制动系统的道路车辆的制动效率。同样适用于电子制动系统（EBS），其目的是确保不同测试仪的可比测量结果，从而在进行滚筒制动测试的地方，对行车制动系统的效率进行可靠评估。购买本文件时可获得的所有当前修订均包含在购买本文件中。

This part ISO 21069 specifies a roller brake test for determining the braking efficiency of road vehicles having a maximum authorized total mass (Code ISO-MO8) as defined in ISO 1176 of more than 3,5 t, being of categories M2, M3, N2, N3, O3 and O4 as defined in UNECE R.E.3 and equipped with full power air (pneumatic) braking systems. Also applicable to electronic braking systems (EBS), its purpose is to ensure comparable measurement results from different testers, leading to reliable assessment of the efficiency of service braking systems wherever roller brake tests are performed.All current amendments available at time of purchase are included with the purchase of this document.